Minimally invasive endovascular techniques have come to the forefront in the safe and expeditious use of embolectomy devices for thromboembolic clot extraction. Currently employed devices generally extract the clot using a combination of balloons, graspers, aspiration, and wire retrievers. These devices attempt to remove the clot in vivo by attaching to it and then pulling it through the vascular lumen and out of the body. With these devices the thrombus is typically not fully contained and if fragments of the clot break away, they may become new emboli in the blood stream. That is to say that existing devices typically maintain partial or full exposure of the thrombus within the vascular lumen and when clot extraction is attempted the “bare thrombus” can pose a threat of fragmentation or partial clot dislodgement which can predispose a patient to inadvertent distal embolization, non-target territory embolization or incomplete thrombus extraction.
Additionally, in order to limit the blood flow in the clotted vessel during clot removal, many procedures utilize a variety of flow arrest techniques such as balloon-assisted proximal vessel occlusion to minimize antegrade flow in an effort to exclude distal clot fragmentation during clot extraction. Mechanical or assisted suction techniques are oftentimes utilized simultaneously via the balloon flow arrest catheter to capture any potential embolic debris during clot extraction. However, complete flow arrest in the brain arteries is often difficult due to extensive intracranial collaterals (e.g. Circle of Willis), limiting the efficacy and utility of proximal flow arrest and suction in the carotid circulation. Even limited blood flow can create a significant risk of clot fragmentation and distal migration of clot during extraction.
Completely encasing the clot captured within the stent-retriever by isolating the thromboembolism and excluding it from the vascular flow channel would eliminate or markedly reduce the risk of embolization.